Recently, as a market of imaging apparatuses such as the digital still camera has become very large, users have varied demands for digital still cameras. Needless to say, not only demands for an increase in image quality, a decrease in size, and a decrease in thickness, but also demands for an increase in magnification and the fastness of the photographic lens and an increase in viewing angle have become very strong.
Generally, among the zoom lenses which can be provided in the imaging apparatuses, a so-called positive lead type zoom lens, of which the lens group closest to the object side has a positive power, takes advantages that the zoom ratio can be set to be high and the optical system can be designed to be fast in the entire zoom range. Accordingly, the positive lead type zoom lenses, which are appropriate to achieve high magnification for example a zoom ratio of 10 or more magnifications, have been mostly used.
As the positive lead type zoom lens, there is a zoom lens constituted of four or more groups which include three lens groups respectively having positive, negative, and positive refractive powers in order from the object side to the image side (for example, refer to JP-A-2006-23529, 2005-338740, 2010-48855, 2007-10695 and Japanese Patent No. 3977150).
JP-A-2006-23529, 2005-338740, 2010-48855, and Japanese Patent No. 3977150 disclose zoom lenses each of which is constituted of four groups having positive, negative, positive, and positive refractive powers in order from the object side to the image side.
JP-A-2007-10695 discloses a zoom lens, which is constituted of four groups having positive, negative, positive, and positive refractive powers in order from the object side to the image side, and a zoom lens which is constituted of five groups having positive, negative, positive, positive, and positive refractive powers in order from the object side to the image side.